Apparatus for investigating earth formations



sept. s, 1959 M. P. LEBOURG l APPARATUS FOR INVESTIGATING EARTH FORMATIONS .All 1- Il l 1/14 5 Sheets-Sheet 1 FIG. l

INVENTOR. MAURICE P. LEBOURG.

Hls ATToRNEY.

Sept. 8, 1959 M. P. LEBOURG 2,903,068

APPARATUS FOR INVESTIGATING EARTH FORMATIONS Filed Sept. A'2.3, 1955 l 3 Sheets-Sheet 2 FIG. 2

INVENTOR.

MAURICE P, LEB OURG.

BY www HIS ATTORNEY.

Sept. 8, 19,59 M.V P. LEBOURG A 2,903,068

APPARATUS FOR INVESTIGATING EARTH FORMATIONS INVENTOR.

MAURICE P. LEBouRG.

HIS ATTORNEY.

United States vPatent @hice 2,903,068 Patented Sept. 8, 1959 APPARATUS FOR UNVESTIGATING EARTH FORMATIONS Maurice P. Lebourg, Houston, Tex., assignor, by mesne assignments, to Schlumberger Well Surveying Corporation, Houston, Tex., a corporation of Texas Application september z3, 1955, serial No. `536,115

1-0 claims. (ci. 16a-100) This invention lrelates to apparatus for investigating earth formations and, more particularly, pertains toa new and -improved .projectile for use in an :earth formation luid sampler.

One type 'of `iluid sampler proposed heretofore 'comprises :a `hollow projectile disposed within 'a gun block adapted to be lowered through a borehole Vto a position adjacent a formation rof interest. At the 'desired level, `an explosive Vcontained 'by the gun block is 'detonated thereby Vto re the projectile into the formation. The projectile is connected to a reservoir by a exible tube and has a normally closed front aperture which 'isopened so that formation fluid may pass through the projectile 'and the flexible tube into the reservoir where itis 'retained biy means of a check valve. 'Phe apparatus may 'then 'be raised vto the Fsurface l'where lthe `sample `can be recovered from the reservoir.

Experience has :shown that when a solid object penetrates Aa formation, its physical characteristics change; -usual'ly the result is 'in the nature 'of compaction of the formation. For example, if an objec't .is forced into a y'sand body which does not `change in volume, the voids in the sand body are decreased by the volume of the object. Such #a deereaseordinalrily `taikes place in the immediate vicinity of the object.

As these voids 'are decreased, thesand 7grains arelpushed into Eone another in such a manner that they are crushed into l'an extremely fine material, yand the yperr'neability `of the sand immediately adjacent the surface of the object approaches Tzero. Thus, 4it may be diicult, if not impossible, to obtain a sample 'of fluid from many -formations.

1t is an object `of the ypre'sent invention, therefore, to provide a new and improved projectile for an rearth formation -iiuid sampler which overcomes the 'undesirable effects of compaction lof formation lmaterial into 'which theprojeetile is driven.

Another object ofthe .present 'invention vis to provide 'a new and improved :projectile rfor an vearth formation 'fluid `sam-ple Vfor obtaining Asamples yof 'formation fluids 'with greater reliability than heretofore possible.

in accordance with the present f inventio'n, a .projectile for an earth formation -fluid sampler comprises a body adapted to be impelled toward a selected earth formation and having `a chamber. A w'a-ll .portionof the body has an opening fluidly communicable with the chamber and a closure for the opening is movable from one .position blocking the opening to another .fpositionpermittin'g fluid to ow through the opening. A speed 4control device is mechanically connected between the ebody Aand the closure for "governing the frate of motion of the closure between its two positions.

The novel features 'of ithe present viifiol'l ar jSet 'forthwith particularity in theappended claims. "The present invention, both as to its organization and manner of operation, together with further 'object fand advantages thereof, may lbest be understood by i'e'fe'renc'eto the Ifollowing description taken in connection with `the accompanying ydrawings which:

Fig. l is a view in longitudinal cross section of an earth formation fluid sampler incorporating ya projectile embodying the present invention, the fluid sampler being represented schematically and in one condition 'of operation;

Fig. 2 isa View similar 'to the one shown in Fig. L1, but illustrating the uid sampler `in another condition of 'operation; and

Fig. 3 represents another 'form'of projectile for an earth formation uid sampler embodying the present invention.

In Fig. 1 of the drawings there is illustrated a portion 'of a 'sampler unit 1'0 including agun block and a sample- -receiving Acha'mb'er 12. vSampler unit 10 may be con* 'structed in the manner described in the Vcopen'cling -application of R. Q. Fields filed September 23, 1955, bearing the Serial No. 536,204, and assigned to the same assignee as the present invention. Although but a single unit is illustrated, any desired 'number of units 'may 'be employed vand `the entire assembly vis suspended in a bore- ?hole l13 by a cable (not shown) in "the customary manner.

Borehole 13 traverses earth formations lsuch as the one designated 14, `1S,'and 1:6 and may be lled with a 'drilling uid y17.

VDisposed within a cylindrical, vtransverse bore 1'8 of 'gun `block l11 is a cylindrical, 4hollow Aprojectile A19 embodying fthe present invention. The projectile 19 has a rear end portion i2@ very slightly smaller than bore 1'8 and a O-ring -21 seated in an annular groove `22 provides a uid seal between 'end portion A20 and the wall of ibo're I8. A tapered section extends between rear portion 20 and ato'rward 'portion T24 of a smaller fdia'rneter, =terminated by -a Yfrusto-"conical nose section 2'5 through which a lco-axial 1opening or cylinder Z6 ex'tends. This type of projectile construction fincludi'nga forward portion smaller than a rear portion is `disclosed in the c'op'ending application of Maurice Mennicier filed September 23, 1955, bearing the Serial No. 536,251, and assigned to the same assignee las -the present invention. Y

Cylinder 26 is 4'closed by 4a piston-like closure L27 having a forward surface v218 of conical configuration which, in the position shown for the closure, forms a continuation of surface 25. A iluid seal between :pstonf27 and cylvinder 2'6 is assured by means `of an -rin'g 29 seated in ari-annular groove'SO in the piston.

Closure 27 is normally in the position Aillustrated which 'may rbe Adeii'ned vas a first position blocking opening 2'6 and, as will be more apparent :from the discussion jto follow, may move to an intermediate position and thereafter is movable to a second position within a chamber 31 that is `connected xto opening 2'6 and 'o'f a larger diameter. Thus, in 'thes'ec'ond position of lthe -cflosu're 27, fluid is permitted to -o'w through opening '26 and into hainber 3'1. A shear Ering '32 3is seated in Aan annular groove 33 in the outer surface of 'closure 127 and is positioned to lenga-ge an annular, forward vjta'orticnl `27" of the projectile body dennedby the junction of the 'wall of k(mening 2b land surface 2:5. Accordingly,j shear 32 functions as the :locking means for preventing 'relativemovement betweenportion I2:1 'of the body "of the projectile and closure 27 lfrom the 'aforesaid 'rst position `in response to "the Ap'ressi'i're of the Ad'rilliiclg 'mud v*17 in borehole Ring 32, however, is frangibl'ein'-1"esp'onse to a sudden impact on closure 27 when the projectile is virr'i'pel'lecl into a formation to pennit movement of `'the closure to an intermediate rposition wherein openingz remains closed,

A speed control device is connected lbetween the pro jectile body 'and the closure 'for governing the rate of motion lof thelclosure between its intermediate an'dseco'nd positions. For example, Ya delayedeetoirash-pet may be utilized including a piston 34 supported concentrically within chamber 31 and a co-operating cylinder 35 extending co-axially through the rear end of closure 27. A forward section 36 of cylinder 35 is of slightly larger diameter and is adapted to be substantially iilled with an appropriate liquid 37, such as mineral oil. However, chamber section 36 is not entirely filled with liquid 37, a small amount of air at atmospheric pressure being provided so as to permit unimpeded movement of the closure 27 under impact conditions whereby shear ring 32 may be broken.

Chamber 31 is filled with a uid at a pressure lower than the pressure of formation uids; for example, it may contain air at atmospheric pressure. Thus, in operation a pressure differential exists which produces movement of the closure 27 from its intermediate to its second position. By providing a given amount of clearance between piston 34 and cylinder section 35 and using a liquid 37 of selected viscosity, the liquid 37 escapes into chamber 31 at a relatively slow irate thereby to govern the rate of motion of the closure.

Disposed at the rearmost end of chamber 31 is a iilter unit 38 comprised of a cylindrical end portion 39 appropriately secured, as by being clamped within a recess 40 in the wall of the chamber. A cylindrical portion 41 of reduced diameter extends forwardly from portion 39 and is integral with piston 34 thereby providing a support for the piston. A conduit 42 extends co-axially through members 40, 41 and terminates at approximately the junction between member 41 and piston 34. A plurality of radial openings 43 fluidly connect conduit 42 with the exterior surface of portion 41 and a co-axial filter screen 44 of cylindrical configuration is appropriately secured, such as by being soldered, at its extremities to the extremities of iilter portion 41.

A closure seal 45 seals the rear end of the projectile 19 and has an axial opening 46 for receiving one end of a flexible tube 47 to which it is mechanically connected in an appropriate manner. For example, the tube may be silver soldered to the wall of opening 46 and an enlarged head 48 is provided on the tube. Thus, the tube is fluidly sealed to the wall of opening 46, while head 48 affords a strong mechanical connection for forward movement with closure 45. Tube 47 is in iluid communication with chamber 31 via lter unit 38 and is wound into a plurality of helical turns disposed at the rear end of gun bore 18. The remaining extremity of tube 47 is fluidly connected to a conduit 49 that extends to sample-receiving chamber 12.

A propellant such as an explosive material 50 is disposed at the rear end of gun bore 18 and within the convolutions of tube 47. An electrical igniter 51 extends through a transverse opening 52 in gun block 11 into the bore 18 where it is in contact with explosive 50.

To condition the apparatus for operation, closure 27 and chamber 12 are installed at the surface of theA earth. Chambers 12 and 31 may be evacuated or iilled with a fluid at a pressure lower than the pressure of formation fluids. For example, these chambers may contain air at atmospheric pressure when the apparatus is lowered into bore hole 13. As pointed out hereinbefore, shear ring 32 prevents movement of closure 27 in response to the pressure of drilling mud 17. After gun block 11 of unit is positioned adjacent formation 15, an appropriate electrical circuit is completed between a source of electrical energy (not shown) and igniter 51 thereby to detonate explosive 50 and projectile 19 is impelled out of the gun bore 18 into the formation. Tube 47 uncoils and extends from the gun bore thereby permitting projectile 19 to enter the formation. The force of the impact between closure 27 and formation material ruptures shear disk 32, but only slight movement of the closure is permitted because of the dash-pot action of liquid 37. Since chamber 31 is normally at atmospheric pressure, after the projectile 19 remains in the formation for a sutlicient length of time, lthe vcontinued formation -pressure acting on surface 28 of closure 27 slowly pushes the closure back into chamber 31. The escape of fluid 37 through the clearance between piston 34 and cylinder 35 into chamber 31 permits this movement lto occur at a controlled, slow rate. Thus, closure 27 moves from its intermediate position to its second position illustrated in Fig. 2. It will be observed that in the latter position closure is clear of opening 26 and formation fluid can enter opening 26 and ow through chamber 31, filter unit 38, tube 47, conduit 49 and into the samplereceiving chamber 12.

Since surface 28 of closure 27 is forced away from the formation material penetrated by projectile 19 and closure 27 moves so as to open the cylinder 26, a space is provided into which compacted formation material may fall under the influence of formation pressure. Of course, once the compacted material is removed, formation fluid may readily flow. Consequently, by using a projectile embodying the present invention, samples of formation iluid may be consistently and reliably taken.

After chamber 12 is filled, unit 10 is drawn upwardly to close a valve (not shown) in the iiuid path to the chamber and to break the tube 47. Thereafter, the unit may be raised to the surface of the earth where the sample is removed.

ln a modified arrangement of Fig. 3, where elements similar to corresponding elements in Fig. l are identied by the same reference numerals, projectile 19' is provided with a closure 27 having a cylinder 60 which receives piston 34. If desired a fluid seal may be provided by means of an O-ring 61 seated in an annular groove 62 in the piston 34. Cylinder 60 is adapted to be filled with an appropriate liquid 63 and is iluidly connected by an oriiice 64 to an auxiliary chamber 65 in the forward end of closure 27. The orifice is small enough to prevent flow due to the liquid viscosity and surface tension of liquid 63 and therefore the tendency of fluid to flow is minimized. Cylinder 60 is not entirely iilled with liquid 63 to permit a slight movement wherein shear disk 32 may be ruptured upon impact with a formation.

After the projectile 19' is imbedded in a formation, and subsequent to the rupture of shear disk 32, the formation pressure acting on surface 28 of closure 27 forces it backward along opening 26 by acting against the atmospheric pressure within principal chamber 31. The rate of motion of closure 27 is governed by the rate of uid flow from cylinder 60 through orifice 64 into auxiliary chamber 65. Accordingly, a dash-pot action is provided in the arrangement of Fig. 3 and, in general, the operation is essentially the same as described in connection with the embodiment illustrated in Figs. 1 and 2.

Although speed control devices of the dash-pot type have been illustrated, obviously other types may be aphave been shown and described, it is apparent that changes and modifications may be made without departing from this invention in its broader aspects. Therefore, the aim in the appended claims is to cover all such changes in modifications as fall within the true spirit and scope of this invention.

I claim:

1. In an earth formation fluid sampler, a projectile comprising: a body adapted to be impelled from a gun bore toward a selected earth formation, said body having a rearward and forward portion, said rearward portion having a chamber, said forward portion having a bore extending between said chamber and opening to a forward exterior surface of said body; a piston-like closure for said bore including a forward surface extending beyond said body and adapted to engage the wall of a borehole, said closure, having-a one operative position blocking said b'ore fand thereby maintaining a pressure lower than formation Ipres'sure in said chamber, and movable through said bore in response `to 'formation pressure on said forward, surface to another operative position permitting fluid to flow through said bore; and a speed control device connected between Vsaid body and said closure for governing the rate kof motion of said closure between its aforesaid positions.

2. In Van earth formation fluid sampler, a projectile comprising: la body adapted to be impelled toward a selectedv earth formation, having a chamber, and including a wall portion having an opening fluidly communicable with said chamber; a closure for said opening movable from one position blocking said opening to another position permitting ylluid to llow through said opening; and a speed control device including Aco-operating piston and cylinder sections operatively connected between said body and said closure, said cylinder being adapted to be substantially lilled with a liquid and said piston and said cylinder having suflicient clearance to permit said liquid to escape from said cylinder at a predetermined rate thereby to govern the rate of motion of said closure between its aforesaid positions.

3. In an earth formation duid sampler, a projectile comprising: a body adapted to be impelled toward a selected earth formation having a chamber and including a wall portion having an opening fluidly communicable with said chamber; a closure for said opening movable from one position blocking said opening to another position permitting -uid to llow through said opening; and a speed control device including a piston disposed in said chamber and connected to said body, and a co-operating cylinder in a portion of said closure, said cylinder being adapted to be substantially lled with a liquid and said piston and said cylinder having sufficient clearance to permit said liquid to escape from said cylinder into said chamber at a predetermined rate thereby to govern the rate of motion of said closure between its aforesaid positions.

4. In an earth formation uid sampler, a projectile comprising: a body adapted to be impelled toward a selected earth formation having a principal chamber and including a wall portion having an opening fluidly communicable with said principal chamber; a closure for said opening movable from one position blocking said opening to another position permitting lluid to flow through said opening; and a speed control device including a piston and a co-operating cylinder operatively connected between said body and said closure, said device further including an auxiliary chamber and an orifice fluidly connecting said cylinder and said auxiliary chamber, said cylinder being adapted to be substantially filled with a liquid and said orifice permitting liquid to llow at a predetermined rate from said cylinder to said auxiliary chamber thereby to govern the rate of motion of said closure between its aforesaid positions.

5. In an earth formation fluid sampler, a projectile comprising: a body adapted to be impelled toward a selected earth formation having a principal chamber and including a wall portion having an opening fluidly communicable with said principal chamber; a closure for said opening movable from one position blocking said opening to another position permitting fluid to llow through said opening; and a speed control device including a piston disposed in said chamber and connected to said body, said closure including a portion having a cylinder coperating with said piston, having an auxiliary chamber and having an orifice lluidly connecting said cylinder and said auxiliary chamber, said cylinder being adapted to be substantially filled with a liquid and said orifice permitting liquid to llow at a predetermined rate from said cylinder to said auxiliary chamber thereby to govern the rate of motion of said closure between its aforesaid positions.

6. In an earth formation fluid sampler, a projectile comprising: a body adapted to be impelled from a gun bore toward a selected earth formation, said body including a rearward portion and forward portion, said rearward portion having a chamber, said forward portion including a wall portion having an opening lluidly communicable with said chamber; a closure for said opening movable from one position blocking said lopening to another position permitting uid to flow through said opening, said closure having a portion thereof extending beyond the forward portion of the body and adapted to engage the wall of a borehole; and a speed control device connected between said body and-said closure for governing the rate of motion of said closure between its aforesaid positions thereby to block the fluid flow through said opening for an interval of time.

7. In an earth formation iluid sampler, a projectile comprising: a body adapted to be impelled from a .gun bore toward a selected earth formation, said body having a rearward and forward portion, said rearward portion having a chamber, said forward portion including a wall portion having an opening lluidly connected to a front section of said chamber, said body having a fluid passage lluidly connected to a rear section of said chamber; a lluid lter disposed in said rear section of said chamber for permitting formation fluid to flow therethrough while excluding extraneous formation material; a closure for said opening movable from one position blocking said opening to another position permitting fluid to flow through said opening, said closure having a portion thereof extending beyond the forward portion of the body and adapted to engage the wall of a borehole; and a speed control device connected between said body and said closure for governing the rate of motion of said closure between its aforesaid positions.

8. In an earth formation Huid sampler, adapted to be lowered into a borehole containing a drilling liquid, a projectile comprising: a body adapted to be impelled from a gun bore toward a selected earth formation, said body having a rearward and forward portion, said rearward portion having a chamber, said forward portion including a wall portion having an opening fluidly communicable with said chamber; a closure for said opening movable from a lirst position blocking said opening to a second position permitting fluid to flow through said opening, said closure having a portion thereof extending beyond the forward portion of the body and adapted to engage the wall of a borehole; locking means for preventing relative movement between said body and said closure from said first position in response to pressure of drilling liquid in a borehole, but releasable in response to a sudden impact on said closure when said body is impelled into a formation to permit movement of said closure to an intermediate position wherein said opening remains closed; and a speed control device connected between said body and said closure for governing the rate of motion of said closure between its aforesaid intermediate and second positions.

9. In an earth formation fluid sampler adapted to be lowered into a borehole containing a drilling liquid, a projectile comprising: a body adapted to be impelled from a gun bore toward a selected earth formation, said body having a rearward and forward portion, said rearward portion having a chamber, said forward portion including a Wall portion having an opening fluidly communicable with said chamber; a closure for said opening movable from a first position blocking said opening to a second position permitting fluid to llow through said opening, said closure having a portion thereof extending beyond the forward portion of the body and adapted to engage the wall of a borehole; a locking member connected to said closure and engageable with a portion of said body for preventing relative movement between said body and said closure from said first position in response to pressure of drilling liquid in a borehole, said locking member being frangible in response to a sudden impact on said closure when said body is impelled into a formation to permit movement of said closure to an intermediate position wherein said opening remains closed; and a speed control device including co-operating piston and cylinder sections operably connected between said body and said closure, said cylinder being adapted to be substantially lled with a fluid and said piston governing the rate o motion of said closure between its aforesaid intermediate and second positions.

10. In an earth formation fluid sampler, a projectile comprising: a body adapted to be impelled from a gun bore toward a selected earth formation, having a cham ber, and including a wall portion having an opening fluidly communicable with said chamber; a closure for said opening movable from one position blocking said opening to another position permitting fluid to ow through said opening, said closure having a portion thereof extending beyond the forward portion of the body and adapted to engage the wall of a borehole; and a delay action dash-pot including relatively movable portions, one of said portions connected to said body and another of said portions connected to said closure for governing the rate of motion of said closure between its aforesaid positions thereby to block fluid flow through said opening for an interval of time after the projectile is in the formation.

References Cited in the file of this patent UNITED STATES PATENTS 2,286,673 Douglas June 16, 1942 2,526,695 Schlumberger Oct. 24, 1950 2,626,777 True Ian, 27, 1953 2,799,474 Schneersohn July 16, 1957 FOREIGN PATENTS 1,065,044 France Dec. 30, 1953 

1. IN AN EARTH FORMATION FLUID SAMPLER, A PORJECTILE COMPRISING: A BODY ADAPTED TO BE IMPELLED FROM A GUN BORE TOWARD A SELECTED EARTH FORMATION, SAID BODY HAVING A REARWARD AND FORWARD PORTION, SAID REARWARD PORTION HAVING A CHAMBER, SAID FORWARD PORTION HAVING A BORE EXTENDING BETWEEN SAID CHAMBER AND OPENING TO A FORWARD EXTERIOR SURFACE OF SAID BODY; A PISTON-LIKE CLOSURE FOR SAID BORE INCLUDING A FORWARD SURFACE EXTENDING BEYOND SAID BODY AND ADAPTED TO ENGAGE THE WALL OF A BOREHOLE, SAID CLOSURE, HAVING ONE OPERATIVE POSITION BLOCKING SAID BORE AND THEREBY MAINTAINING A PRESSURE LOWER THAN FORMATION PRESSURE IN SAID CHAMBER, AND MOVABLE THROUGH SAID BORE IN RESPONSE TO FORMATION PRESSURE ON SAID FORWARD SURFACE TO ANOTHER OPERATIVE POSITION PERMITTING FLUID TO FLOW THROUGH SAID BORE; AND A SPEED CONTROL DEVICE CONNECTED BETWEEN SAID BODY AND SAID CLOSURE FOR GOVERNING THE RATE OF MOTION OF SAID CLOSURE BETWEEN ITS AFORESAID POSITIONS. 